LG 50PS3000 only displaying bottom half of screen

[Scottie7275]

Hello everyone.

First time repairing a tv. As above my LG 50PS3000 has suddenly stopped displaying the top half of the screen, like the attached picture.

After a little reading I figured it would be the top buffer board so I replaced it but still have the same problem.

I watched a video on YouTube about how to test a buffer board and have tried testing them both and they both seem to be ok. Not sure I was doing it correctly though!!!

My question is, what else could it be? And how do I test to see what it is?

Thanks

[tom66]

Re: LG 50PS3000 only displaying bottom half of screen

Most likely it would be something wrong with the signals going to the top buffer since you have ruled out the buffer itself, that would point to control board or possibly main board. It is also possible a damaged or loose cable could cause this so it is worth checking those. (The cables can corrode if the air is humid, or come loose if the TV is moved or over time due to thermal expansion.)

Can you see if the white lines go away on a completely black screen?

Have you tried activating the test pattern mode? (It requires putting a small jumper wire across some pins on a board.)

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

Hi Tom.

Thanks for your reply.

Attached is a picture of what should be a completely black screen.

I haven't done the test screen thing as I have no idea how!

Thanks

Scott

[tom66]

Re: LG 50PS3000 only displaying bottom half of screen

Interesting...
Can you post a picture of your control board?
It's the green board in the centre of the set - has a load of white ribbon cables coming out of it.
Also, check that you connected the cable between the two buffers correctly. If that's loose weird shit can happen.

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

I will do that tomorrow Tom, it's bedtime now!!!

Thanks for your help so far!

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

Ok so I checked the connections and all seem OK. I did notice however that the lines on the screen are far less with the replacement buffer board than the original one. I don't know if that means anything or not? I have included pics as well as a pic of the control board.

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

And this is the pic of the screen with the new buffer board in.

[ReeceyBurger123]

Re: LG 50PS3000 only displaying bottom half of screen

Run the test patterns like Tom said.

[vinceroger69]

Re: LG 50PS3000 only displaying bottom half of screen

Run the test patterns like Tom said.

Reading this post i think it needs a test jig for these? tom has posted in the below thread,
https://www.badcaps.net/forum/showthread.php?t=34550

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

Where do I get a test jig?

Starting to think it might be easier to buy a new tv?

[ReeceyBurger123]

Re: LG 50PS3000 only displaying bottom half of screen

Remove Lvds cable, on cntrl board there are a few pins that stick up jumper/short them out thwn turn Tv on. Screen will flash Red,white, blue etc.

[finntricky]

Re: LG 50PS3000 only displaying bottom half of screen

Remove Lvds cable, on cntrl board there are a few pins that stick up jumper/short them out thwn turn Tv on. Screen will flash Red,white, blue etc.

its the white block that has AUTO GEN under it, in the bottom left of the t-con, as in your picture, but cant remember the 2 pins to short,

[vinceroger69]

Re: LG 50PS3000 only displaying bottom half of screen

this thread does seem too have the top lines like your set has
https://www.badcaps.net/forum/showthread.php?t=41599

[ReeceyBurger123]

Re: LG 50PS3000 only displaying bottom half of screen

its the white block that has AUTO GEN under it, in the bottom left of the t-con, as in your picture, but cant remember the 2 pins to short,

That's what I was referring too.

[ReeceyBurger123]

Re: LG 50PS3000 only displaying bottom half of screen

Hey seen your selling this Tv on ebay, why have you given up ?

[Alastair E]

Re: LG 50PS3000 only displaying bottom half of screen

Ive had that fault--Replacement y-sus fixed it....

I think it as one of the octal-buffers on the y that had gone...

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

Hi Reece,

Wife said if I was going to spend more money then she would have a 3D TV instead!!

I feel a bit out of my depth to be honest and didn't want to throw more money at it to get nowhere. I thought about buying a Y-sus board just out of curiosity but wife said to just get a new tv! Might do that anyway after just reading the last post!

I really appreciate everyone's help!

[ReeceyBurger123]

Re: LG 50PS3000 only displaying bottom half of screen

Fair enough just dont get an Led Tv ! Avido Led/Lcd and go Oled buddy you wont regret it. If not give it ago, you can send the boards back on ebay anyway.

[Scottie7275]

Re: LG 50PS3000 only displaying bottom half of screen

Hello again!

So i decided to get a new Y-sus board and fitted it this morning.

It has worked but I now have a single black horizontal line right in the middle of the screen!

Any ideas?

Thanks

[Alastair E]

Re: LG 50PS3000 only displaying bottom half of screen

Reseat the buffer-tabs from screen to buffer-boards in line with the defect--they are quite a fiddle to do--And delicate....
--They dont click in when fully home--they sorta 'nunk' in--You'll know what I mean once you've done one right...